大鼠急性心肌梗死后骨髓干细胞归巢于缺血心肌的时间窗研究

目的：初探心肌梗死后骨髓干细胞归巢于心肌组织的时间窗。 方法： 110只大鼠随机分为4组，GM-CSF干预组(n=40)皮下注射GM-CSF (50 μg/kg/d) 5 d，对照组(n=40)皮下注射同等剂量生理盐水，GM-CSF干预假手术组(n=15)，对照假手术组(n=15)，结扎左冠状动脉前降支复制急性心肌梗塞动物模型，同时复制假手术模型。各组在心梗后1 、3 、5 、10 d免疫组化法观察心肌组织中归巢的ckit+细胞数量，28 d测定血压、室内压及±dp/dt值变化，观察两组大鼠瘢痕组织修复差异。 结果： ①心梗后28 d GM-CSF干预组心功能显著高于对照组(P<0.05)；②GM-CSF干预组瘢痕组织横径显著高于对照组(P<0.05)，梗死区平均心肌面积显著高于对照组(P<0.05)；③GM-CSF干预组与对照组1，3，5 d均有ckit+细胞归巢现象，以第5 d最为密集，第10 d未再有新归巢的ckit+细胞，GM-CSF干预组各时点ckit+细胞归巢数量显著高于对照组(P<0.05)。 结论： 骨髓干细胞归巢的时间窗为心梗后10 d以内。

Time window of bone marrow stem cell homing to ischemia myocardium after acute myocardial infarction in rats

AIM: To investigate the time window of bone marrow stem cell homing to the inchemia myocardium. METHODS: 110 SD male rats were randomly divided into four groups: GM-CSF-treated group (n=40) and sham-treated group (n=15) were given GM-CSF (50 μg/kg/d) for 5days. The control group (n=40) and its sham-treated group (n=15) was injected equal volume of saline, acute myocardiar infarction were induced by LAD ligation in each group. At 1, 3, 5, 10 days in each group, the homed bone marrow stem cells were detected by expression of c-kit with immunohistochemical methods. Cardiac performance and pathological changes were examined at 28 days. RESULTS: At 28 days, both systolic function and diastolic function in GM-CSF-treated group were significantly higher than those in control group (P<0.05). Histological observation indicated that the tissue repair in GM-CSF-treated group was significantly higher than that in control group (P<0.05). The GM-CSF-treated group and control group both had the homed c-kit+ cells at 1, 3 and 5 days. At 5 days, both had high number of c-kit+ cells, but the homed c－kit+ cells in GM-CSF-treated group were significantly higher than that in control group (P<0.05) at 1, 3 and 5 days (P<0.05). At 10 days both group had no new homed c-kit+ cells. CONCLUSION: The time window of BMSC homing is within 10 days after AMI in rats.